ORGANS OF THE BODY. 549 



The nerves of the uterus have been very carefully investigated by Fran- 

 kenhduser. They are derived from the genital or spermatic ganglia, and 

 through these from the so-called plexus uterinus magnus and p. hypo- 

 gastrici, to which branches of the sacral nerves are given off. 



On the posterior wall of the neck of the uterus is situated a ganglionic 

 mass of considerable size, the ganglion cervicale of Lee. From this most 

 of the nerves supplying the organ take their rise beside vaginal and 

 vesical twigs. Only a very small number come from ihep. hypogastricus. 

 The course of the nerves in the walls of the organ usually corresponds 

 with that of the blood-vessels ; it is, however, very hard to follow. In 

 regard to the ganglia found here, we refer to 189. The termination 

 also of the filaments in the muscular substance has been likewise dealt 

 with in 183. 



In the ligamenta lata bundles of unstriped fibres are to be found 

 between their two layers. The round ligaments are, however, still more 

 richly supplied with these elements, besides which they contain volun- 

 tary fibres. On the other hand, the lig. ovarii are but slightly muscular. 

 During menstruation the uterus becomes looser in texture and increased 

 in volume owing to a great influx of blood into it at this time. At the 

 same time, the glands of the mucosa increase considerably both in 

 length and breadth. A discharge of blood takes place also from the 

 gorged capillaries of the mucous membrane, the walls of the latter being 

 either ruptured in the act, or, by the passage, as some believe, of red cor- 

 puscles through the uninjured walls. The blood of menstruation, which 

 is poured out at the external genitals (p. 121), is found besides to contain 

 a large admixture of cast-off uterine epithelium. 



During pregnancy the uterus undergoes a considerable increase in 

 volume, affecting principally the muscular layers, and, as microscopical 

 analysis has shown, consisting in a remarkable growth of the contractile 

 fibre-cells ( 173) (which may now be easily separated from one another) 

 as well as in a multiplication or neoplasis of the same, at least at the 

 commencement of the period. 



Both the blood-vessels and lymphatics, as might be expected, partici- 

 pate also in this increase in size. 



It is also an interesting fact, that the nerves of the uterus becomes 

 thicker and grayer at the same time through thickening of their peri- 

 neurium, while the individual fibrillee present a darker outline than 

 before, so that they can now be followed farther into the parenchyma 

 (Kilian). That the number of primitive fibrillse actually becomes larger 

 is a matter greatly to be doubted. 



We must now bestow a few words on the most important of all the 

 changes which take place here, namely, the metamorphosis of the mucous 

 membrane. Already before the arrival of the ovum in the cavity of the 

 uterus this structure becomes thicker, softer, and more vascular. Further, 

 its fibrous elements gaining in number, and the uterine glands increasing to 

 'four or five times their original length, a separation takes place between it 

 and the inner surface of the uterus. Covering the ovum, now it is known 

 as the decidua. After parturition a new mucous membrane and new glands 

 are formed on the surface of the uterine cavity, a regeneration of which 

 neither of the two tissues are capable under normal circumstances. The 

 involuntary fibres of the womb undergo, about the same time, fatty 

 degeneration, retrograde development, and partial destruction. 



